A flyback transformer is generally implemented within the circuits of a display device for providing distinctive voltages required by the circuits operation of the display device. Some U.S. Patents, i.e. U.S. Pat. Nos. 5,160,872, 5,287,479 and 4,144,480 may be referred in order to have an in-depth understanding of structures of the flyback transformer and functions of the High Voltage output, Focus output and Screen output of the flyback transformer.
Please refer to FIGS. 1 and 2. FIG. 1 is a schematic diagram of a flyback transformer 10 according to the prior art. FIG. 2 is an exploded diagram of the flyback transformer 10 shown in FIG. 1. Flyback transformer 10 of the prior art comprises a low-voltage bobbin 12, a high-voltage bobbin 14, an upper core 16, a lower core 18 and a housing 20. The assembly procedure of the flyback transformer 10 comprises: first, installing a winding shaft (not shown) of the low-voltage bobbin 12 into a shaft hole (not shown) of the high-voltage bobbin 14; secondly, installing the low-voltage bobbin 12 and high-voltage bobbin 14 into the housing 20; finally, mounting the upper and lower cores 16, 18 on the low-voltage bobbin 12 to form the flyback transformer 10.
In general, a clip 22 is often used to mount the upper and lower cores 16, 18 on the low-voltage bobbin 12 within the assembly procedure of the flyback transformer 10. The clip 22 is made of nonmagnetic metallic material with good flexibility to achieve the purpose of mounting the upper and lower cores 16, 18. However, the use of clip 22 increases the cost, and more particularly, a side opening 25 must be provided on the low-voltage bobbin 12 for receiving the lower core 18. Finally, it always leads to decrease the structural rigidity of the low-voltage bobbin 12. As a result, a shrinkage problem arises within the injection process of the low-voltage bobbin 12. A plurality of sockets 24 provided on the low-voltage bobbin 12 would displace and fail to comply with the original design requirement.
Based on the above issues, a re-positioning process of the sockets is usually required during the injection process between the low-voltage bobbin 12 and the high-voltage bobbin 14 in order to enforce a pin 26 corresponding to each socket 24 back to its original position as possible. Nevertheless, the result of the re-positioning process also fails to comply with the original design requirement because of stress recovery.
Please refer to FIG. 3. FIG. 3 is a schematic diagram of a reinforced rib 28 of the low-voltage bobbin 12 according to the prior art. With respect to the above-mentioned problem of socket displacement in the low-voltage bobbin 12, a rectangular reinforced rib 28 is provided on a skirt 29 to increase the structural rigidity of the low-voltage bobbin 12. However, the existence of the reinforced rib 28 will affect the assembly procedure of the upper and lower cores 16, 18. Therefore, the reinforced rib 28 should be punched off to create said side opening 25 for receiving the lower core 18 before the assembly procedure of the upper and lower cores 16, 18.